Daterange picker

[kilobyte2007]

In this PR I have added:

1. Date range capability to the datepicker component
2. Fixed the bug in datepicker where a Vue 2 :value was used instead of :model-value
3. Got rid of the scrollIntoView helper method and used a native DOM method which works better as it doesn't rely on fixed pixel offset which worked inconsistently when scaling.

We really needed this functionality in our app so we decided to implement this. I have also added some doc examples. Please let me know what you think.